Remove hardcoded port in Prometheus learned_mac export.
Remove hardcoded port in Prometheus learned_mac export.

trentindav/faucet,mwutzke/faucet,Bairdo/faucet,anarkiwi/faucet,trungdtbk/faucet,trentindav/faucet,gizmoguy/faucet,wackerly/faucet,mwutzke/faucet,gizmoguy/faucet,REANNZ/faucet,faucetsdn/faucet,byllyfish/faucet,byllyfish/faucet,shivarammysore/faucet,Bairdo/faucet,faucetsdn/faucet,trungdtbk/faucet,wackerly/faucet,shivarammysore/faucet,REANNZ/faucet,anarkiwi/faucet